<template>
  <div>
<div class="shopcart">
  <div class="content" @click="toggleList">
    <div class="content-left">
      <div class="logo-wrapper">
        <div class="logo" :class="{'highlight':totalCount >0}">
          <i class="icon-shopping_cart" :class="{'highlight':totalCount >0}"></i>
        </div>
        <div class="num" v-show="totalCount>0">{{totalCount}}</div>
      </div>
      <div class="price" :class="{'highlight':totalPrice >0}">￥{{totalPrice}}</div>
      <div class="desc">另需配送费￥{{deliveryPrice}}元</div>
    </div>
    <div class="content-right" @click.stop.prevent="pay"> // stop阻止点击事件的冒泡、prevent阻止默认事件
      <div class="pay" :class="payClass">
        {{payDesc}}
      </div>
    </div>
  </div>
  <div class="ball-container">
    <div v-for="ball in balls" :key="ball.id">
    <transition name="drop" @before-enter="beforeEnter" @enter="enter" @after-enter="afterEnter">
        <div v-show="ball.show" class="ball">
          <div class="inner inner-hook"></div>
        </div>
    </transition>
    </div>
  </div>
  <transition name="fold">
    <div class="shopcart-list" v-show="listShow">
      <div class="list-header">
        <h1 class="title">购物车</h1>
        <span class="empty" @click="empty">清空</span>
      </div>
      <div class="list-content" ref="listContent">
        <ul>
          <li class="food border-bottom" v-for="food in selectFoods" :key="food.id">
            <span class="name">{{food.name}}</span>
            <div class="price">
              <span>￥{{food.price*food.count}}</span>
            </div>
            <div class="cartcontrol-wrapper">
              <cart-con-trol :food="food"></cart-con-trol>
            </div>
          </li>
        </ul>
      </div>
    </div>
  </transition>
</div>
  <transition name="fade">
    <div class="list-mask" @click="heideList" v-show="listShow"></div>
  </transition>
  </div>
</template>

<script>
  import CartConTrol from '../../components/cartcontrol/CartConTrol'
  import Bscroll from 'better-scroll'
   export default {
      name: 'ShopCart',
     components: {
       CartConTrol
     },
     props: {
        // 储存一个数组，每一个food的个数以及价格
        selectFoods: {
          type: Array,
          default () {
            return []
          }
        },
       deliveryPrice: {
         type: Number,
         default: 0
       },
       minPrice: {
         type: Number,
         default: 0
       }
     },
     data () {
       return {
         balls: [
           {
             show: false
           },
           {
             show: false
           },
           {
             show: false
           },
           {
             show: false
           },
           {
             show: false
           }
         ],
         dropball: [],
         fold: true
       }
     },
     watch: {
       selectFoods (newFoods, oldFoods) {
         if (newFoods.length === 0) {
           this.fold = true
         }
       }
       },
     computed: {
        // 计算总价
        totalPrice () {
          let total = 0
          this.selectFoods.forEach((food) => {
            total += food.price * food.count
          })
          return total
        },
       // 计算food数量
       totalCount () {
          let count = 0
         this.selectFoods.forEach((food) => {
           count += food.count
         })
         return count
       },
       // 支付描述
       payDesc () {
          if (this.totalPrice === 0) {
            return `￥${this.minPrice}元起送`
          } else if (this.totalPrice < this.minPrice) {
            let diff = this.minPrice - this.totalPrice
            return `还差￥${diff}元起送`
          } else {
            return '去结账'
          }
       },
       payClass () {
          if (this.totalPrice < this.minPrice) {
            return 'not-enough'
          } else {
            return 'enough'
          }
       },
       listShow () {
          let show = !this.fold
         if (show) {
           this.$nextTick(() => {
             if (!this.scroll) {
               this.scroll = new Bscroll(this.$refs.listContent, {
                 click: true
               })
             } else {
               this.scroll.refresh()
             }
           })
         }
         if (!this.totalCount) {
           // this.fold = true
           return false
         } else if (this.totalCount > 0 && !this.fold) {
           return true
         }
         return false
       }
     },
     methods: {
        drop (el) {
          for (let i = 0; i < this.balls.length; i++) {
            let ball = this.balls[i]
            if (!ball.show) {
              ball.show = true
              ball.el = el
              this.dropball.push(ball)
              return
            }
          }
        },
       // 定义三个钩子函数实现动画
       beforeEnter (el) { // el为当前执行transition动画的DOM对象
         let count = this.balls.length
         while (count--) {
           let ball = this.balls[count]
           if (ball.show) {
             let rect = ball.el.getBoundingClientRect() // 获得元素相当于视口的位置
             let x = rect.left - 32
             let y = -(window.innerHeight - rect.top - 22)
             el.style.display = ''
             // 外层元素是纵向的动画，内层元素是横向的动画
             el.style.webkitTransform = `translate3d(0, ${y}px, 0)`
             el.style.transform = `translate3d(0, ${y}px, 0)`
             let inner = el.getElementsByClassName('inner-hook')[0]
             inner.style.webkitTransform = `translate3d(${x}px, 0, 0)`
             inner.style.transform = `translate3d(${x}px, 0, 0)`
           }
         }
       },
       enter (el) {
         // 浏览器重绘
         /* eslint-disable no-unused-vars */ // 必须添加声明 否则会报错
         let rf = el.offsetHeight
         this.$nextTick(() => { // 样式重置
           el.style.webkitTransform = 'translate3d(0, 0, 0)' // 没有变量时只能用单引，不能用反引
           el.style.transform = 'translate3d(0, 0, 0)'
           let inner = el.getElementsByClassName('inner-hook')[0]
           inner.style.webkitTransform = 'translate3d(0, 0, 0)'
           inner.style.transform = 'translate3d(0, 0, 0)'
         })
       },
       afterEnter (el) {
         let ball = this.dropball.shift() // 删除并返回第一个ball
         if (ball) {
           ball.show = false // 重置ball.show的状态
           el.style.display = 'none'
         }
       },
       toggleList () {
          if (!this.totalCount) {
            return
          }
          // this.listShow = false
          this.fold = !this.fold
       },
       empty () {
          this.selectFoods.forEach((food) => {
            food.count = 0
          })
       },
       heideList () {
          this.fold = true
       },
       pay () {
          if (this.totalPrice < this.minPrice) {
            return
          }
          window.alert(`支付${this.totalPrice}元`)
       }
     }
   }
</script>

<style lang="stylus" scoped>
  .shopcart
    position fixed
    left 0
    bottom 0
    z-index 50
    width 100%
    height 48px
    .content
      display flex
      background #141d27
      font-size 0
      color rgba(255, 255, 255, 0.4)
      .content-left
        flex 1
        .logo-wrapper
          display inline-block
          position relative
          top -10px
          margin 0 12px
          padding 6px
          width 56px
          height 56px
          box-sizing border-box
          vertical-align top
          border-radius 50%
          background #141d27
          .logo
            width 100%
            height 100%
            border-radius 50%
            background #2b343c
            text-align center
            &.highlight
              background rgb(0, 160, 220)
            .icon-shopping_cart
              line-height 44px
              font-size 24px
              color #80858a
              &.highlight
                color #fff
          .num
            position absolute
            top 0
            right 0
            width 24px
            height 16px
            line-height 16px
            text-align center
            border-radius 16px
            font-size 9px
            font-weight 700
            color #fff
            background rgb(240, 20, 20)
            box-shadow 0 4px 8px 0 rgba(0, 0, 0, 0.4) // 盒子阴影、参数以此为水平、垂直、模糊距离、模糊尺寸、阴影颜色
        .price
          display inline-block
          vertical-align top
          margin-top 12px
          line-height 24px
          box-sizing border-box
          padding-right 12px
          border-right 1px solid rgba(255, 255, 255, 0.1)
          font-size 16px
          font-weight 700
          &.highlight
            color #fff
        .desc
          display inline-block
          vertical-align top
          line-height 24px
          margin 12px 0 0 12px
          font-size 10px
      .content-right
        flex 0 0 105px
        width 105px
        .pay
          height 48px
          line-height 48px
          text-align center
          font-size 12px
          font-weight 700
          background #2b333b
          &.not-enough
            background #2b333b
          &.enough
            background #00b43c
            color #fff
    .ball-container
      .ball
        position fixed
        left 32px
        bottom 22px
        z-index 200
        transition all 0.4s cubic-bezier(0.49, -0.29, 0.75, 0.41) // 贝塞尔曲线
        .inner
          width 16px
          height 16px
          border-radius 50%
          background rgb(0, 160, 220)
          transition all 0.4s linear //x轴做一个线性的过渡即可
    .shopcart-list
      position absolute
      top 0
      left 0
      z-index -1
      width 100%
      transition all 0.3s
      transform translate3d(0, -100%, 0)
      &.fold-enter-active, &.fold-leave-active
        transform translate3d(0, 0, 0)
      .list-header
        height 40px
        line-height 40px
        padding 0 18px
        background #f3f5f7
        border-bottom 1px solid rgba(7, 17, 27, 0.1)
        .title
          float left
          font-size 14px
          color rbg(7, 17, 27)
        .empty
          float right
          font-size 12px
          color rgb(0, 160, 220)
      .list-content
        padding 0 18px
        max-height 217px
        background #fff
        overflow hidden
        .food
          position relative
          padding 12px 0
          border-bottom rgba(7, 17, 27, 0.1)
          .name
            line-height 24px
            font-size 14px
            color rgb(7, 17, 27)
          .price
            position absolute
            right 90px
            bottom 12px
            line-height 24px
            font-size 14px
            font-weight 700
            color rgb(240, 20, 20)
          .cartcontrol-wrapper
            position absolute
            right 0
            bottom 6px
  .list-mask
    position fixed
    top 0
    left 0
    width 100%
    height 100%
    z-index 40
    backdrop-filter blur(10px)
    transition all 0.5s
    opacity 1
    background rgba(7, 17, 27, 0.6)
    &.fade-enter, &.fold-leave
      opacity 0
      background rgba(7, 17, 27, 0)
</style>
